AN AMERICAN general told Peter Singer once that insurgents most fear America’s unmatched technology. Then, talking to a Lebanese newspaper editor as a drone circled overhead, he heard a different story: Americans and Israelis, the editor said, are cowards to send machines to fight for them. Much of the ethical conversation around America’s unmanned aerial vehicle strikes in Afghanistan and Pakistan has centered around unintended civilian casualties. This is certainly a worthy topic for conversation. But Mr Singer asked a different set of questions: how do drones change the nations that use them?

Mr Singer, the author of “Wired for War” and a senior fellow at the Brookings Institution, a think tank, spoke this week at the IdeaFestival in Louisville. He made it clear, first, that drones are not merely an American phenomenon. More than 40 countries, he says, are building robotic combatants. No country can hold a first-mover advantage for long. For America, however, the consequences are not only strategic, but constitutional. A president who sends someone’s son or daughter into battle has to justify it publicly, as does the congress responsible for appropriations and a declaration of war. But if no one has children in danger, is it a war?